The Observer suggests detailed plans on troop withdrawal are being drawn up by UK, US and Iraqi officials and will be presented to the Iraqi parliament next month.

It quotes military sources as saying the document would lay out a detailed exit "road map" by multinational forces.

Defence Secretary John Reid denied there was any such plan but told Sky News' Sunday with Adam Boulton: "In the course of next year, there could be the start of the process of the handover to the Iraqis."

When counter-terrorism operations had been handed over, Mr Reid said, "There will then be a process - it won't happen overnight - where they gradually take the lead, we gradually withdraw to barracks and we gradually withdraw from Iraq itself."

Tory leader Michael Howard told the same programme: "I think that if we were to leave prematurely we would leave behind a country that would be in danger of becoming a real hotbed of international terrorism and that would be a disaster.

"So we must do what we set out to do - we must continue to work towards the achievement of a stable, sustainable and peaceful Iraq."